1. The Field of the Invention
The present invention relates to the manufacture of semiconductor devices. More particularly, the present invention is directed to methods for performing a wet clean of a composite surface, i.e., a surface having at least two materials exposed, where the composite surface is situated on a semiconductor wafer. The methods are particularly useful during the manufacture of a semiconductor device for a post chemical mechanical polishing clean of a surface having an exposed interface of silica and nitride, silica and low .kappa. dielectric, or nitride and low .kappa. dielectric, where .kappa. (lower kappa) is intended to represent the dielectric constant.
2. The Relevant Technology
Wet clean processes used in semiconductor manufacturing are typically applied to surfaces of uniform composition. While the contamination to be removed may of course have a different composition, the surface to be cleaned is itself generally of uniform composition, i.e., all silica, all silicon, all silicon nitride, etc. In certain instances, however, it has become desirable to perform wet cleaning on a composite surface, a surface having at least two different materials exposed, such as at least two of silica, silicon, nitride, low .kappa. dielectric, and other materials used in the formation of semiconductor devices. For example, where chemical mechanical polishing is used to planarize a layer of silica stopping on nitride, both silica and nitride are exposed on the resulting planarized surface. Such composite surfaces are not well cleaned by standard wet cleans. Particulate contamination is especially difficult to remove from composite surfaces with standard wet cleans. Thus, an improved method for wet cleaning composite surfaces is needed.